1. Field of the Invention
The invention relates to integrated circuit testing method, program, storing medium, and apparatus for automatically forming a test pattern of a dynamic function test and testing, more particularly, to integrated circuit testing method, program, storing medium, and apparatus in which a failure detection ratio of a dynamic function test for detecting a delay failure by applying a system clock is improved, thereby shortening a processing time.
2. Description of the Related Arts
In recent years, an influence by delay failures which are mixed due to a variation in manufacturing processes of LSIs has been increasing due to the realization of a high speed and microminiaturization of a circuit, and those delay failures cannot be detected if only a conventional low-speed static function test (SFT) is used. Therefore, sufficient test quality cannot be guaranteed with respect to the operation in a state where the LSI is actually assembled into a system. Therefore, there has been proposed a dynamic function test (DFT) in which a system clock is supplied as a sending clock, a change is given to a network from a sending FF and propagated, similarly, the system clock is supplied as a receiving clock, and the change is detected by a receiving FF, thereby detecting a delay failure of a path between the sending FF and the receiving FF.
An automatic test pattern generation (ATPG) method of automatically generating a test pattern for such a conventional dynamic function test is used, as a target, for detection of a transition failure which is presumed on the network or for the transferring operation of a path between the specific sending FF and the receiving FF. In this case, as a method of activating the failure propagating path, due to a restriction for improving resolution regarding the detection of the transition failure or the measurement of the specific path serving as a target, that is, due to a restriction for suppressing the occurrence of a hazard, a method of monotonously activating only the propagating path of the transition failure to be detected or the specific path for allowing the transferring operation to be executed is often used.
However, in such a automatic test pattern generation using the conventional activating method of the single path as mentioned above, in all multi-input gates existing on the activating path, states before and after the sending clock need to be aligned to uncontrol values with respect to inputs from paths other than the path to be activated. The test certainly fails in the case where an inevitable change is propagated to the gate input to which the uncontrol value is to be set at timing before and after the sending clock due to re-convergence of the path to be activated or the like. Therefore, it is difficult to obtain the sufficient detection ratio with respect to the transition failure or the specific path for allowing the transferring operation to be executed as a target of the automatic test pattern generation.
In automatic test pattern generation according to the activating method of the single path, since,no change exists in the gate inputs from the paths other than the path to be activated before and after the sending clock, the transition failure which is detected by the test pattern or the specific path which allows the transferring operation to be executed is limited to the transition failure on the path to be activated or the specific path for allowing the transferring operation to be executed. There is a problem such that if it is intended to obtain the highest failure detection ratio as possible, the number of tests which are generated increases. When considering the operation of an LSI assembled in an actual system, a situation such that only the single path is activated in the transfer path from the sending FF to the receiving FF is considered to be a unique case. There is a problem such that a possibility that the operation of the test pattern formed by the conventional testing method is deviated from the operation of the LSI assembled in the actual system is high.